26 TELEOSTOML 



dd. Vertebne amphicoclian (double concave); maxillan- not transversely 



(lividfd; scaK'8 cycloid 1Ialk<oM(>1{IMII, X. 



aa. Arterial bulb thin, with a pair of opposite valves; optic nerves crossing, 

 not fonninj; a solid cbiasnia. (Scries Tklkostei.) 

 e. Air-bladder (if present) connected by an air-duct with the intestinal 

 canal, this persistent throut;liout life; ventral tins (if present) aljdmni- 

 nal, without spines, their basilar segments rudimentai. (Suft-ruyed 

 lishes.) {J'liysostomi.) 

 f. Shoulder girdle attached to the skull by means of a post^temporal bone 

 (suprascapula); form not eel-like. 

 <). I'nicorncoid arch, present. 



h. Maxillary bone imperfect, forming the base of a long barbel ; no 



subopercle nor syniplectic bune ; four anterior vertebra- much 



modilied, co-ossilied, and with an ossicula auditus; supraoccipitals 



and parietals co-ossilied; no scales. . . Nk.matognatmi, XI. 



hh. Maxillary bone ])erfect, not entering into a barbel (rarely entirely 



wanting); subopercle and syniplectic bone present. 



i. Anterior vertebra; modified, co-ossilied, and with the ossicula 



auditus EVENTOONATIII, XII. 



M. Anterior vertebras similar to the others, separate, and without 



ossicula auditus Isosi-oxdyli, XIII. 



gg. PraDCoracoid arch obsolete; anterior vertebra; not modified; parie- 

 tal bones separated by supraoccipital; bead scaly. 



Hapuimi, XIV. 



ff. Shoulder girdle not attached to the skull; no pra-coracoid arch; 



parietal bones in contact; maxillary wanting or united with the 



l)alatines; form eel-like AroDKs, XV, 



ee. Air-bladder without duct (in the adult); ventral fins without basal seg- 

 ments, usually anterior in position; spines usually present in the fins; 

 pectoral tins not on the plane of the abdomen ; parietal bones usu- 

 ally separated by the supraoccipital. (Spiny-rayed fishes chiefly.) 



j. Shoulder girdle connected to the skull by a post-temporal. 

 k. Lower pharyngeals co-ossified ; no spines; ventrals abdominal; lateral 



line on side of abdomen Syxkntounatiu, XVI. 



itit. Lower pharyngeals separate (or united, and the dorsal (in with 

 spines.) 

 /. Gills tufted; pharyngeal bones and most of the branchihyals want- 

 ing; skin with bony plates LopnoBKANCim, XVII. 



U. Gills pectinate (as usual in fishes). 

 m. Superior branchihyals and pharj'ngeals reduced in number ; 



ventrals sub-abdominal IlEMiiiHANriiii. XVIIL 



mm. Superior branchihyals and pharyngeals in normal development. 



n. Ventral fins abdominal I'KKCFisorK.s, XIX. 



nn. Ventral fins thoraiic or jugular. 



o. Pectoral fins not pediculale, the gill openings in front of them. 

 p. Bones of the jaws distinct. 



q. Cranium normal AcAXTHorrKKi, XX. 



qq. Cranium twisted, so that both eyes are on the same side 

 of head; no fiu spines. . . Uetekusumata, XXI. 



